Secondary sensory area SII is crucially involved in the preparation of familiar movements compared to movements never made before

Secondary sensorimotor regions are involved in sensorimotor integration and movement preparation. These regions take part in parietal-premotor circuitry that is not only active during motor execution but also during movement observation and imagery. This activation particularly occurs when observed movements belong to one's own motor repertoire, consistent with the finding that motor imagery only improves performance when one can actually make such movement. We aimed to investigate whether imagery or observation of a movement that was never made before causes parietal-premotor activation or that the ability to perform this movement is indeed a precondition. Nine subjects [group Already Knowing It (AKI)] could abduct their hallux (moving big toe outward). Seven subjects initially failed to make such movement (Absolute Zero A0 group). They had to imagine, observe, or execute this movement, whereas fMRI data were obtained both before and after training. Contrasting abduction observation between the AKI-group and A0-group showed increased left SII and supplementary motor area activation. Comparing the observation of hallux flexion with abduction showed increased bilateral SII activation in the A0 and not in the AKI group. Prolonged training resulted in equal performance and similar cerebral activation patterns in the two groups. Thereby, conjunction analysis of the correlations on subject's range of abduction during execution, imagery, and observation of hallux abduction showed exclusive bilateral SII activation. The reduced SII involvement in A0 may imply that effective interplay between sensory predictions and feedback does not take place without actual movement experience. However, this can be acquired by training.

Synthesis and evaluation of fluorine-18 labelled compounds for imaging of bacterial infections with pet

Syntheses of no carrier added (n.c.a.) 6-fluoro-1,4-dihydro-1-cyclopropyl-4-oxo-7-[4-[18F]fluoro-phenacyl-1-piperacinyl]-chinolincarboxylic acid ([18F]COPCA) and n.c.a. 4-[18F]fluoro-benzoyl-ubiquicidin 29-41 ([18F]UBI 29-41) are described. [18F]COPCA was synthesised within 120 min with a radiochemical yield of 9-12%. [18F]UBI 29-41 was synthesised within 150 min with a radiochemical yield of 15-20%. Both compounds had a specific activity of more than 35 GBq/micromol. The biological activity was verified by measuring its binding to Staphylococcus aureus bacteria. Specific binding was found for [18F]UBI 29-41 (12-17%), whereas no specific binding for [18F]COPCA was found.

Synthesis and evaluation of a 18F-labelled recombinant annexin-V derivative, for identification and quantification of apoptotic cells with PET

In this report, we describe the synthesis of 4-[18F]-fluorobenzoyl-annexin V (4-[18F]FBA). In a four-step procedure, 4-[18F]FBA was synthesised with a microcomputer controlled, automated module within 90min. The radiochemical yield was in the range of 15-20% (corrected for decay) with a specific activity of more than 35GBq/micromol. The specific binding was confirmed by studies of 4-[18F]FBA with phosphatidylserine-containing liposomes. The biological activity of 4-[18F]FBA was verified by measuring its binding to Jurkat T-cell lymphoblasts after induction of apoptosis as compared to control cells without apoptosis. 4-[18F]FBA seems to be a suited tracer to measure apoptotic activity in vivo.

Role of cucurbitacin C in resistance to spider mite (Tetranychus urticae) in cucumber (Cucumis sativus L.)

Cucurbitacins are bitter triterpenoid compounds that are toxic to most organisms and occur widely in wild and cultivated Cucurbitaceae. The only cucurbitacin identified in Cucumis sativus is cucurbitacin C. The bitter taste of cucumber has been correlated with resistance to the spider mite Tetranychus urticae, but a quantitative relationship has not been established. We determined the spider mite resistance and cucurbitacin C content in the dihaploid progeny derived from the F1 generation of a cross between a bitter, spider-mite-resistant cucumber line and a bitter-free, spider-mite-susceptible line. The ratio of the number of bitter to bitter-free dihaploids conformed to the expected 1:1 ratio, based on a monogenic segregation pattern. Genetic analysis ascribed 69% of the variance of the difference in spider mite survival rate to the bitterness locus. Within the group of bitter dihaploids, cucurbitacin C content was significantly correlated with spider mite resistance. Thus, a quantitative relationship between cucurbitacin C content and spider mite resistance could be established.

Validation of the limulus amebocyte lysate (LAL) test for routine PET radiopharmaceuticals

The kinetic turbidimetric limulus amebocyte lysate test was validated as method for detecting endotoxins in short-lived radiopharmaceutical samples. Using this method, radiopharmaceuticals can be released for administration to humans after the test, without extensive loss of radioactivity. Inhibition or enhancement on the LAL results by the product samples were examined in more detail and eliminated.

N-[18F]-fluoroalkylation of noraporphines: microwave versus thermal treatment

A comparable study of microwave versus thermal heating is described for the N-[18F]-fluoroalkylation of noraporphines. As compared to thermal treatment, different products were obtained during microwave treatment. Thermal treatment resulted in the loss of the protection of the catechol functionality of the noraporphines (O-deacylation), whereas during microwave treatment N-[18F]-fluoroalkylation was observed. The results described in this report might suggest that the influence of microwaves on chemical transformations is not exclusively thermal.

Synthesis and in vivo distribution in the rat of several fluorine-18 labeled N-fluoroalkylaporphines

A method is described for the rapid production and purification of new potential dopamine agonists. Via microwave heating 10,11-dihydroxy-N-(n-2-fluoroethyl)norapomorphine (FNEA), 10,11-dihydroxy-N-(n-3-fluoropropyl)norapomorphine (FNPA) and 2,10,11-trihydroxy-N-(n-3-fluoropropyl)norapomorphine (FTNPA) and their isotopic fluorine-18 derivatives were synthesized. The fluorine-18 label was introduced via N-fluoroalkylation of acylated noraporphine derivatives with no-carrier-added (n.c.a.) 18FCH2CH2I and 18FCH2CH2CH2I. Within 160 min (E.O.B.), radiochemical yields of 13-29% (corrected for decay) were achieved based on [18F]fluoroalkyliodide. The specific activity obtained, ranged from 15 to 75 GBq/mumol. The fluorine-18 labeled compounds were investigated for their in vivo binding potency to the D2-receptors. After i.v. injection, the distribution was studied in rats. High uptakes of the N-[18F]fluoroalkylaporphines were found in the lungs, liver, adrenals and kidneys. No significant different radioactive accumulation was observed in striatum, cerebellum and frontal cortex. Dopamine depletion with reserpine did not affect the striatum to cerebellum ratio at low dosage of N-[18F]fluoroalkylaporphines (10 nmol/kg).

Synthesis and in vivo distribution in the rat of several fluorine-18 labeled 5-hydroxy-2-aminotetralin derivatives

A method is described for the rapid production and purification of new potential dopamine agonists. Via thermal heating (refluxing in an oil bath) and microwave exposure 2-[N-n-3-fluoropropyl-N-(4-methylphenyl)ethylamino]-5-hydroxyte tralin (12), 2-[N-n-3-fluoropropyl-N-(4-fluorophenyl)ethylamino]-5-hydroxyte tralin (13), and their isotopic fluorine-18 derivatives were synthesized, respectively. The fluorine-18 label was introduced via N-fluoroalkylation with no-carrier-added (n.c.a.) 18FCH2CH2CH2I. In 115 min, radiochemical yields of 11% (corrected for decay) were achieved for both compounds. The specific activity ranged from 15-75 GBq/mumol. After i.v. injection in rats, the fluorine-18 labeled compounds were evaluated for their in vivo binding to the D2-receptors. The radioactivity levels in the striatum, nucleus accumbens and tuberculum olfactorius were not significantly higher than in the cerebellum and frontal cortex at 15, 30 and 60 min after administration of the tetralin derivatives. Dopamine depletion with reserpine did not affect the uptake in the dopamine D2-receptor rich area. Remarkable high uptakes were found in the adrenal for both compounds.

Synthesis and in vivo distribution in the rat of a dopamine agonist: N-([11C]methyl)norapomorphine

A method for the rapid production and purification of 10,11-dihydroxy-N-([11C]methyl)norapomorphine ([11C]APO), a dopamine agonist (DA), is described. The potency of this ligand for studying the D2-receptors was examined. The label was introduced by N-methylation of norapomorphine hydrobromide with no-carrier-added (n.c.a) [11C]CH3I, produced from cyclotron-produced [11C]carbon dioxide. In 60 min (EOB) a radiochemical yield of 15% (corrected for decay) was achieved, based on [11C]CH3I. The specific activity ranged from 5 to 11 GBq/mumol. The distribution, after intravenous injection, was studied in rats. The radioactivity level in the striatum was higher than in the cerebellum and frontal cortex and was decreased after D2-blockade. The highest uptake ratio (1.47) was found at 30 min after injection. Dopamine depletion with reserpine did increase the striatum/cerebellum ratio at a low dosage of [11C]APO (10 nmol/kg). High uptakes of [11C]apomorphine were found in the lungs, liver and kidneys.

Positron emission tomographical studies of 1-11C-acetoacetate, 2-18F-fluoro-deoxy-D-glucose, and L-1-11C-tyrosine uptake by cat brain with an experimental lesion

In cat brain with a freezing injury, the uptake of 1-11C-acetoacetate (11C-ACAC), 2-18F-fluorodeoxy-D-glucose (18FDG), and L-1-11C-tyrosine (11C-TYR) was monitored by positron emission tomography following intravenous administration of the tracers, at 1 day, and 1-3 weeks after the injury. The development and further course of the cold-induced oedema was monitored by magnetic resonance imaging. In the fresh (1 day old) lesion there was increased uptake of 11C-ACAC, probably due to release of the restrictive influence of the blood-brain barrier upon passage of the substance into brain. The uptake of 18FDG, which normally occurs by carrier-mediated transport at the barrier, was decreased in the fresh lesion, probably as a result of damage of the carrier mechanism. In the 3 week old lesion 18FDG uptake was still reduced, and 11C-ACAC uptake was still increased, although barrier function to Evans blue had recovered. It is suggested, that the increased 11C-ACAC uptake in the chronic lesion bears upon the proliferation of macrophages and reactive glial cells in the lesion. This is supported by the increased uptake of 11C-TYR in the 2 weeks old lesion, while in the fresh lesion 11C-TYR uptake was unchanged.